sys-prog-3-exp2.c

#include <sys/types.h>
#include <unistd.h>
#include <stdlib.h>
#include <pthread.h>

void* thread_function(void *arg);

int run_row = 1;
pthread_mutex_t work_mutex;

int main() {
    int print_count = 0;
    pthread_t a_thread;

    if (pthread_mutex_init(&work_mutex, NULL) != 0) {
        perror("Mutex init failed\n");
        exit(1);
    }

    if (pthread_create(&a_thread, NULL, thread_function, NULL) != 0) {
        perror("Thread creation failed\n");
        exit(1);
    }
    if (pthread_mutex_lock(&work_mutex) != 0) {
        perror("Lock failed\n");
        exit(1);
    } else {
        printf("Main Lock!\n");
    }
    while (print_count++ < 5) {
        if (run_row == 1) {
            printf("Main thread is running\n");
            run_row = 2;
        } else {
            printf("Main thread is sleep\n");
            sleep(1);
        }
    }
    if (pthread_mutex_unlock(&work_mutex) != 0) {
        perror("unlock failed\n");
        exit(1);
    } else {
        printf("Main unlock\n");
    }
    pthread_join(a_thread, NULL);
    pthread_mutex_destroy(&work_mutex);
    exit(0);
}

void *thread_function(void *arg) {
    int print_count = 0;

    if (pthread_mutex_lock(&work_mutex) != 0) {
        perror("Thread Lock failed\n");
        exit(1);
    } else {
        printf("Function Lock!\n");
    }

    while(print_count++ < 5) {
        if (run_row == 2) {
            printf("function thread is running\n");
            run_row = 1;
        } else {
            printf("function thread is sleep\n");
            sleep(1);
        }
    }
    if (pthread_mutex_unlock(&work_mutex) != 0) {
        perror("Thread unlock failed\n");
        exit(1);
    } else {
        printf("Function unlock!\n");
    }
    pthread_exit(NULL);
}